Method for the separation of a fluid from a medium flowing in a duct

ABSTRACT

Devices for measuring at least one parameter of a medium flowing in a line, having an inlet conduit an outlet conduit, having the disadvantage in the prior art that liquids flowing into the inlet conduit can reach a measurement element and alter the measurement characteristic curve behavior of the measurement element. A device ( 1 ) of the invention has, between the inlet conduit ( 24 ) and outlet conduit ( 44 ), a deflection conduit ( 33 ) with a separation element ( 70 ), by which the liquids are separated out and therefore do not reach the measurement element ( 60 ).

PRIOR ART

[0001] The invention is based on a device for determining at least oneparameter of a flowing medium and on a method for separating a liquidfrom a medium flowing in a line, as generically defined by the preamblesto claims 1 and 14, respectively.

[0002] A device with a measurement conduit is already known (GermanPatent Disclosure DE 197 35 891 A1) in which a measurement element isaccommodated that is bathed there by the inflowing medium. The mediumflows from an inlet conduit first into a deflection conduit, which has alarger flow cross section than the inlet conduit and has a right-angledcorner, so that there is an abrupt flow transition in the form of a stepto the inlet conduit. Next, deflected by the corner of the deflectionconduit, the medium flows along the peripheral face of the deflectionconduit into an outlet conduit adjoining it transversely and leaves theoutlet conduit through an outlet opening and then mixes again with themedium flowing past the device.

[0003] An inlet conduit longitudinal axis and an outlet conduitlongitudinal axis are inclined by a predetermined angle from thelongitudinal axis of the line, so that the inlet conduit has a regionthat is shaded from a main flow direction. The measurement element isdisposed in the shaded region of the measurement conduit, to preventsoiling and resultant defects in the measurement element.

[0004] Water entering the intake line, for instance if the roadway iswet with rain, can sometimes cause contamination of the measurementelement. Natural components of dissolved salts contained in thissplashing water then cause a drift in the characteristic curve of themeasurement element, because of the formation of a salt crust on thediaphragm of the sensor part. Although the inclination of themeasurement body does form a partitioned-off region, nevertheless liquidparticles reach the measurement conduit.

[0005] From German Patent Disclosure DE 197 41 031 A1, a measuringdevice with an inlet conduit is known in which a speeding up of the flowin the inlet conduit can be maintained by the design of two walls of theinlet conduit, but it is known that this leads only to stabilizing theflow of the medium in the inlet conduit, in particular in themeasurement conduit.

ADVANTAGES OF THE INVENTION

[0006] The device and method according to the invention having thecharacteristics of the bodies of claims 1 and 14, respectively, have theadvantage over the prior that a measurement element is protected againstliquid in a simple way.

[0007] By the provisions recited in the dependent claims, advantageousrefinements of and improvements to the device recited in claim 1 arepossible.

[0008] It is advantageous to embody a liquid separation element in aconduit at least partly in labyrinthine fashion, because in this wayliquid can be separated out yet liquid from the outside cannot penetrateinto the conduit.

[0009] It is advantageous to embody the liquid separation element in aninner wall of a deflection conduit of the device, because this improvesthe separation.

[0010] Internested annular-arclike elements, which are simple to producefrom a technical standpoint, are an advantageous embodiment of theliquid separation element.

[0011] It is advantageous to increase the flow resistance of the liquidseparation element compared to the flow resistance of a measurementconduit, because as a result the great majority of the gaseous componentof the flowing medium remains in the measurement conduit.

[0012] It is also advantageous to provide a deflection conduit in theinlet conduit that deflects the flow from the inner wall, because thedeflection of the flow is facilitated thereby.

[0013] For good separation of liquid, it is advantageous that there is adetachment edge in the deflection conduit, which prevents depositedwater from moving in the form of a wall film into the measurementconduit.

[0014] To stabilize the measurement signal, it is advantageous that theflow cross section of the inlet conduit and/or the outlet conduitnarrows in the flow direction.

DRAWING

[0015] Exemplary embodiments of the invention are shown in simplifiedform in the drawing and explained in further detail in the ensuingdescription.

[0016] Shown are:

[0017]FIG. 1, a device according to the invention;

[0018]FIG. 2, a detail of a section through FIG. 1;

[0019]FIG. 3, a section taken along the line III-III of FIG. 2;

[0020]FIG. 4, a section taken along the line IV-IV of above FIG. 2;

[0021] and FIG. 5, a further exemplary embodiment of the device of theinvention.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0022]FIG. 1 schematically shows how a device 1 of the invention isincorporated in a line 3 within which the medium, which is a gas-liquidmixture, flows.

[0023] The device 1 comprises a measurement housing 6, represented by alower rectangle drawn in dot-dashed lines, and a carrier housing 7,represented by an upper rectangle drawn in dot-dashed lines, in whichlatter housing an electronic evaluation unit, for instance, isaccommodated. The measurement housing 6 and carrier housing 7 can mergeintegrally with one another or can be individual parts that are joinedtogether. The measurement housing 6 and the carrier housing 7 have acommon longitudinal axis 10, which can for instance also be a centeraxis. The carrier housing 7 for instance protrudes partway out of theline 3.

[0024] The measurement housing 6 has a side face 8, which is located inthe plane of the drawing.

[0025] The device 1 is introduced, for instance in plug-in fashion, intoa wall 15 of the line 3. The plastic or metal wall 15 defines a flowcross section, in the center of which a center axis 16 extends in thedirection of the flowing medium, parallel to the wall 15. The directionof the flowing medium, hereinafter called the main flow direction, isindicated by corresponding arrows 20 and extends from left to right inthe drawing.

[0026]FIG. 2 shows the plan view on the measurement housing 6 in asectional plane parallel to the plane of the drawing in FIG. 1, with aconduit 22 that has an inlet conduit 24 into which the medium flowsthrough an inlet opening 25. There is an inlet conduit flow direction 29in the inlet conduit 24. Disposed at the end of the inlet conduit 24 isa deflector element 33, which deflects the flow from an inner wall intoa deflection conduit 40, which causes a detachment downstream andimproves a phase separation of the individual mixture components. In thedeflection conduit 40, the flowing medium is deflected and flows into anoutlet conduit 44, which at least in part also forms a measurementconduit 47. An outlet conduit flow direction 50 prevails in the outletconduit 44. In the measurement conduit 47, the medium flows past atleast one measurement element 60, which is disposed on a sensor carrier56. At the end of the outlet conduit 44, the medium strikes an outflowelement 51, as a result of which the medium is deflected and thus flowsback into the line 3. By means of the outflow element 51, the flowdirection of the medium in the outlet conduit 44 is rotated at leastpartway around the longitudinal axis 10. The medium emerging through atleast one outlet opening 53 (FIG. 4) then flows approximately in themain flow direction 20. This improves the measurement signal performancein the case of reverse flows.

[0027] The outlet opening 53 or the outlet conduit 44 can, however, alsobe designed as in DE 197 41 031 A1, which is hereby incorporated byreference.

[0028] Disposed in the deflection conduit 40 on its outer periphery is aseparation element 70, which is embodied, for instance on its inner wall41 facing in the main flow direction 20, in labyrinthine fashion. Theseparation element 70 has at least one separation inlet 64 and at leastone separation outlet 68, which connect the deflection conduit 40 withthe line 3 and through which a liquid separated out at the wall passesout of the deflection conduit 40 into the line 3.

[0029] To prevent too much gas from leaving the inlet conduit 24 throughthe separation element 70, the flow resistance of the separation element70 is increased over that of the inlet conduit 24 and outlet conduit 44.

[0030] A sharp outflow edge 73 is disposed in the inlet conduit 24 or inthe deflection conduit 40, for instance on the deflector element 33;this edge prevents a liquid, such as water, deposited on a lower sidewall 42 of the inlet conduit 24 from participating in the deflection inthe measurement conduit 47 in the form of a wall film in the directionof the measurement element 60. The wall film detaches at the outflowedge 73 from the side wall 42 of the inlet conduit 24 and is entrainedby the flow. Because of the greater inertia of the liquid compared tothe gas, the liquid strikes the outer inner wall 41 of the deflectionconduit 40, for instance, where it can form a wall film again. This wallfilm migrates through the separation inlet 64 into the separationelement 70 and leaves it through the separation outlet 68 into a rearchamber 71. The medium that is deflected in the deflection conduit 40and forced against the inner wall 41 by centrifugal forces pushes thewall film into the separation inlet 64 in the process. At an upper sidewall 43 of the inlet conduit 24, which is opposite the lower side wall42, for instance, the wall film need not detach from the side wall butinstead is pushed directly into the separation inlet 64.

[0031] Liquids in the conduit 22 that do not form any wall film strikethe inner wall 41 and are thereby separated out of the conduit 22.

[0032] The labyrinthine separation element 70 for instance comprisesthree annular-arc elements 76, which are interested. At least one shunt79 is disposed in the region of the separation outlets 68 and protectsagainst water or liquid entering from the line 3.

[0033]FIG. 3 shows a section taken long the III-III of FIG.

[0034] The conduit 22 narrows in the inlet conduit 24 in the flowdirection 29, so that a stabilization of the flow takes place.

[0035] The rear chamber 71, on the side face 8 along the longitudinalaxis 10, has slits 72 through which the liquid that has been separatedout returns to the conduit 3, in which the liquid no longer causes anynegative effects.

[0036]FIG. 4 shows a section taken along the line IV-IV of FIG. 2.

[0037] The outlet conduit 44 also narrows in the outlet conduit flowdirection 50. Once the flowing medium has flowed past the sensor carrier56 with the measurement element 60, it strikes the outflow element 51.The outflow element 51 is embodied in the shape of a W, for instance,and deflects the outlet flow direction 50, so that the medium, throughat least one outlet opening 53, enters the line 3 again and flows onwardin the main flow direction 20 again. In this exemplary embodiment, thereare two outlet openings 53.

[0038] The outflow element 51 protrudes past a side face 54 of themeasurement housing 6. The primary flow 3 creates a negative-pressurezone (detachment) at the outflow element 51 in the region of the outletopening 53 and thus exerts suction on the flow in the measurementconduit 44. Because the outflow element 51 protrudes past the side fact54, a reverse flow that is present in some phases is fed into themeasurement conduit 44 and measured.

[0039]FIG. 5 shows a further exemplary embodiment of the device 1 of theinvention. The difference from the exemplary embodiment of FIG. 2 isessentially that the outlet conduit 44 is the closest to the carrierhousing 7, and the inlet conduit 24 is disposed on a lower end of themeasurement housing 6. Also, the sensor carrier 56 has two measurementelements 60, which measure the volumetric flow and the pressure, forinstance.

1. A device (1) for determining at least one parameter of a mediumflowing in a line (3) in a main flow direction (20), the mediumcomprising a gas-liquid mixture, in particular the aspirated air for aninternal combustion engine, having a measurement housing (6) provided inthe line (3); having a conduit (22) that is disposed in the measurementhousing (6) and has the following properties: the conduit (22) isdivided into an inlet conduit (24), a deflection conduit (40), and anoutlet conduit (44); the conduit (22) has an inlet opening (25), whichis adjoined by the inlet conduit, which in turn is adjoined by thedeflection conduit (40), into which the medium flows from the inletconduit (24) and is deflected, and then flows through the outlet conduit(44) to at least one outlet opening (53), discharging into the line (3)at an outer face (8, 54) of the measurement housing (6); one part of theconduit (22) forms a measurement conduit (47); and having at least onemeasurement element (60) that is located in the measurement conduit (47)and is bathed by the flowing medium, characterized in that a liquidseparation element (70) is integrated with the deflection conduit (40).2. The device of claim 1, characterized in that the liquid separationelement (70) is embodied at least in part in labyrinthine fashion andhas at least one separation inlet (64) and at least one separationoutlet (68).
 3. The device of claim 1 or 2, characterized in that theliquid separation element (70) is embodied in the region of an innerwall (66) of the deflection conduit (40).
 4. The device of one or moreof the foregoing claims, characterized in that the liquid separationelement (70) is formed by at least two internested annular-arclikeelements (76).
 5. The device of one or more of claims 1-4, characterizedin that the flow resistance of the liquid separation element (70) isincreased compared to the flow resistance of the measurement conduit(47).
 6. The device of claim 1, characterized in that a deflectorelement (33) is present in a downstream end of the inlet conduit (24).7. The device of claim 6, characterized in that a detachment edge (73)is disposed on the deflector element (33).
 8. The device of claim 1 or6, characterized in that the device (1) has the measurement housing (6)and a carrier housing (7); that the measurement housing (6) and thecarrier housing (7) have a longitudinal axis (10); that the inletconduit (24) and outlet conduit (44) are disposed one above the otheralong the longitudinal axis (10); and that the inlet conduit (24) is theclosest to the carrier housing (7).
 9. The device of claim 1,characterized in that the device (1) has the measurement housing (6) anda carrier housing (7); that the measurement housing (6) and the carrierhousing (7) have a longitudinal axis (10); that the inlet conduit (24)and outlet conduit (44) are disposed one above the other along thelongitudinal axis (10); and that the outlet conduit (44) is the closestto the carrier housing (7).
 10. The device of one or more of claims 1, 6or 8, characterized in that a flow cross section of the inlet conduit(24) narrows in the flow direction (29) toward the deflection conduit(40).
 11. The device of claim 1 or 9, characterized in that the flowcross section of the outlet conduit (44) narrows in the flow direction(50) toward the outlet opening (53).
 12. The device of one or more ofclaims 1 or 8-11, characterized in that at least one part of the inletconduit (24) and at least one part of the outlet conduit (44) extendinclined relative to the main flow direction (20).
 13. The device ofclaim 1, characterized in that the flow direction of the medium in theoutlet conduit (44) is rotated at least partway around the longitudinalaxis (10), so that the medium emerging via the at least one outletopening (53) then extends approximately in the main flow direction (20).14. A method for separating a liquid in a device (1) for determining atleast one parameter of a medium flowing in a line (3) in a main flowdirection (20), the medium comprising a gas-liquid mixture, inparticular the aspirated air for an internal combustion engine, having ameasurement housing (6) provided in the line (3); having a conduit (22)that is disposed in the measurement housing (6) and has the followingproperties: the conduit (22) is divided into an inlet conduit (24), adeflection conduit (40), and an outlet conduit (44); the conduit (22)has an inlet opening (25), which is adjoined by the inlet conduit, whichin turn is adjoined by the deflection conduit (40), into which themedium flows from the inlet conduit (24) and is deflected, and thenflows through the outlet conduit (44) to at least one outlet opening(53), discharging into the line (3) at an outer face (54) of themeasurement housing (6); one part of the conduit (22) forms ameasurement conduit (47); and having at least one measurement element(60) that is located in the measurement conduit (47) and is bathed bythe flowing medium, characterized in that the liquid in the gas-liquidmixture is carried out of the conduit (22) because of centrifugal forcescaused by the deflection in the deflection conduit (40).